TORONTO (miningweekly.com) – Prospective Northern Ontario chromite miner KWG Resources on Friday announced that it had filed a patent application for a new natural gas chromite reduction method.

The Toronto-based firm, with plans to mine chromite ore at its Black Horse deposit, within the still-unlocked Ring of Fire minerals-rich area, made the patent application ahead of discussions to commercialise the new technique of refining the ore into ferrochrome by means of natural gas.

"It would appear that this process, combining North America's newly discovered high-grade chromite with its also newly discovered wealth of natural gas, could usher a new paradigm into the stainless steelmaking world. This process could in any event enable further processing of the Ring of Fire chromite to occur in Ontario, without special exemptions to its domestic electricity price,” KWG president Frank Smeenk said.

KWG said the development of huge deposits of natural shale gas in the US and in Canada had led to a fall in the long-term cost of natural gas and the prospect of stable pricing for many years to come.

The company pointed out that there were currently no commercially viable chromite deposits in the US and all ferrochrome used in producing steel is imported, typically from South Africa and Kazakhstan. However, significant deposits of such ores were recently discovered in Canada, which is a low-cost natural gas producer, and because of this combination, the invention could be ideally exploited in the Ring of Fire.

The invention uses a modification of the basic and well-established technology used to produce directly reduced iron, to produce a chromium/iron alloy by using natural gas to reduce the oxides of both chromium and iron contained within the chromite ore, the morphology of which had been shown in testing to facilitate the progress of the reduction reactions.

KWG said laboratory work had demonstrated the validity of the process.

Chromite samples from a deposit within the Ring of Fire were successfully reduced to a highly metallised chromium/iron alloy suitable for steelmaking. The temperature required for reducing chromium was much higher than that for reducing iron alone.

The use of an accelerator enabled the reduction process to proceed at an acceptable rate at lower temperatures.

The chromite ore concentrate was supplied as fines and needed agglomeration before the reduction stage. This was accomplished by using a disc pelletiser, commonly available for producing iron-ore pellets. It had also been shown that carbon is a required additive to the chromite to facilitate reduction.

KWG said the process had been shown to produce metallisation levels of chromium and iron of 80% or more. Higher metallisation rates for both chromium and iron could be expected with more process development.

The resulting reduced chromite pellets were suitable for stainless and alloy steelmaking, either as batch or continuously charged components of the steelmaking charge.

Substantial cost advantages were expected when compared with the use of conventionally produced ferrochrome alloys. The carbon content of the reduced chromite could be considerably lower than the ferroalloys produced in a submerged electric arc furnace (SAF).

This would result in significant process advantages for the steelmaker and, therefore, lower its cost of production. The reduced chromite pellets can form part of the charge of a conventional SAF furnace producing ferrochrome, with significant cost benefits.